Method of making a clutch throw-out bearing assembly

ABSTRACT

An improved clutch throw-out bearing assembly and method of making same comprising an antifriction bearing member of either thrust or angular contact variety permanently secured, by staking or the like, to a bearing carrier of formed strip steel, preferably bimetallic, having an integral axially extending portion terminating in a radially outwardly extending flange which with the spaced apart antifriction bearing member form a circumferential groove for receiving the clutch fork or activation member.

This is a division of application Ser. No. 711,753, filed Aug. 4, 1976,now U.S. Pat. No. 4,117,917.

BACKGROUND OF THE INVENTION

Traditionally clutch throw-out bearings have been machined from steeltubes or forgings. It has been common also to machine the bearing innerrace member and the carrier bore as one integral member. This involvesconsiderable expense in time, labor, and material. Scrap from theturning operation on the bearing carrier has been a major source ofwaste. In recent years as metal forming techniques and specializedsteels have been improved, some attempts have been made to form theentire clutch release bearing assembly of sheet metal, as shown in U.S.Pat. No. 3,885,658, for example, with the objective being to reduce costbut maintain performance. This may be satisfactory for light dutyapplications but is inadequate for heavier applications such as theautomobile.

The method and improved clutch throw-out bearing of the presentinvention overcomes many of the problems prevalent in prior artconstructions and techniques providing for improved efficiency,simplicity and economy in manufacture and further providing a bearingassembly of durable operation and versatile design.

BRIEF SUMMARY OF THE INVENTION

The clutch throw-out bearing assembly of the present invention includesan antifriction bearing, one race member of which includes a faceadapted to contact the clutch release fingers and the other race memberis secured to a one piece sheet metal tubular bearing carrier adapted tobe guidably mounted on a support shaft. The bearing carrier is providedwith a member such as a flange on one end portion for engaging anactuation fork and locating and securing means on the other end portionfor positioning and securing the bearings in spaced apart relationshipto the flange. The bearing carrier may also be made of bimetal sheetcomprising a backing strip having a facing of soft metal bearing alloyon one surface thereof with the softer bearing alloy metal being on theinside surface where it slidingly engages the support shaft. Provisionsare also made on the surface of the bearing carrier disposed in contactwith the support shaft for inclusion of recesses that act as reservoirsand distribution means for a lubricant.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a view in elevation and partial cross section showing theassembled relationship between an angular contact bearing, externalcollar, and internal bearing carrier in accordance with this invention.

FIG. 2 is a plan view of the carrier as stamped from flat sheet metalstock before the stamping operation forms it into a generallycylindrical configuration.

FIG. 3 is an enlarged cross-section of the carrier of FIG. 2 at 3--3looking in the direction of the arrows.

FIG. 4 is a view in elevation and partial cross-section showing therelationship of the components in which the bearing is of the thrusttype and the carrier is made from flat bimetal sheet stock.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The preferred embodiment as shown in FIG. 1 includes three general partswhich will be discussed in the following detailed description. Theseparts are a bearing, an outer collar, and an inner sleeve or bearingcarrier. It should be understood, unless specifically stated otherwise,that the term "Bearing" refers to either an angular contact type bearingwhere the race members are disposed in substantially radially opposedrelationship or a thrust bearing where the race members are disposed insubstantially axially opposed relationship to constrain a plurality ofantifriction elements therebetween.

The bearing comprises a first race member 2 with an internalcircumferential ball groove 4 and a radial flange 6 on one end forcontacting clutch release fingers which are not shown. A second racemember 8 includes an external circumferential ball groove 10. Betweenthe outer ball groove 4 and the inner ball groove 10 are confined aplurality of rolling elements 12 which contact the grooves 4 and 10 butare restrained from direct contact with each other by a cage orseparator 14. The internal geometry of the bearing is such that theradial flange 6 of the first race member 2 overlaps and closelyapproaches but does not touch the second race member 8. The flange 6,therefore, serves not only as a surface to actuate the clutch releasefingers (not shown) but also acts as a shield to exclude foreign matterfrom the interior of the bearing on that side.

The first race member 2 of the bearing is partially enclosed by agenerally cylindrical sheet metal collar 20. The collar 20 is retainedon the outside diameter of the first race member 2 such as by aninterference fit and extends axially along the bearing past the endopposite the external race flange 6 where the collar 20 is formed into aradial flange 22. The flange 22 extends inwardly to a position where itsinward annular edge is disposed in spaced clearance relationship to theperiphery of the second race member 8. Flange 22, therefore, forms ashield to exclude foreign matter from entering the bearing on the endopposite the first race flange 6.

In normal practice the first race member 2, the second race member 8,the rolling elements 12, the separator 14, and the outer sheet metalcollar 20 are assembled as an integral unit. The assembled unit is pressfitted onto the carrier 30 and secured in place such as by stakingindicated at 32. The axial location of the bearing on the carrier isestablished by coaction between the edge of the inner race member 8against the locating protrusions 34.

The bearing carrier 30 is produced from a rectangular sheet metalstamping, as shown in FIG. 2, which is cut to size, with the sheetthickness ranging generally from 0.040 to 0.120 inches and 0.060 beingpreferred for automotive use. The ends may be straight to form abutt-joint or include male 36 and female 38 clinches to form aclinch-butt joint coacting in interlocking engagement. The stampingprocess also includes producing the pattern of grease indentations 40, agrease groove 42 and locating protrusions 34. These features may also beseen in cross-section in FIG. 3. A subsequent stamping operation formsthe bearing carrier 30 into the final generally cylindrical shape withthe actuation flange 44 (FIG. 1) formed from the edge portion 50, devoidof any indentation patterns (FIG. 2 and FIG. 3).

FIG. 4 shows another version of the preferred embodiment in which theangular contact race members 2 and 8 of FIG. 1 have been replaced withthrust washer race members 60 and 62. Race member 60 is adapted tocontact the clutch release fingers (not shown) at surface 64 and racemember 62 locates the bearing on the carrier 70 and contacts theactuation fork at surface 66. An outer annular collar 68 not onlyexcludes foreign matter from the contact area of the antifrictionelements but also serves to make the race members 60 and 62 inseparableonce the assembly has been made. One advantage of this embodiment liesin the fact that these race designs are readily adaptable to manufactureby such methods as forging or powdered metallurgical techniques thatinclude compacting and sintering, which reduce waste of material andmachining time. The bearing carrier 70 in FIG. 4 is shown in a formwherein the original sheet metal stock is bimetal comprising a babbittlayer 72 or the like on the inside and a steel backing layer 74 on theoutside. The provision of a soft metal bearing alloy layer such as thebabbitt layer 72, imparts improved performance of the bearing carrierwhere it slidably engages the support shaft (not shown).

In accordance with the embodiment shown in FIG. 1, when pressure isapplied to the throw-out bearing assembly for disengaging the clutch,the force is applied directly to the exposed face 9 of the second racemember 8 which transmits the thrust through the antifriction elements 12to the first race member 2 and the radial flange 6 which contacts theclutch release fingers (not shown). Because of this there is no stressapplied to the bearing carrier 30 except to slide it along a supportmember (not shown). Retraction of the bearing assembly by pressure inthe opposite direction on the radial flange 44, requires only that theweight of the bearing assembly be slidingly moved along the bearingsupport member. Similarly, in accordance with the alternative embodimentshown in FIG. 4, pressure is transmitted from the throw-out bearing face66 of race member 62, through the antifriction elements to race member60 where face 64 contacts the clutch throw-out fingers. For this reasonit is impractical and indeed wasteful to make the bearing carrier 30shown in FIG. 1 or 70 shown in FIG. 4 of the same heavy load bearingconstruction as are the first and second race members.

To those skilled in the art to which this invention relates, manychanges in construction and widely differing embodiments andapplications of the invention will suggest themselves without departingfrom the spirit and scope of the invention. The disclosures and thedescription herein are purely illustrative and are not intended in anyway to be limiting.

We claim:
 1. A method of making a clutch throw-out bearing assemblywhich includes an antifriction bearing with a bearing carrier insertedtelescopically into the bore thereof and securing said bearing carrierto said antifriction bearing by staking or the like, the improvementcomprising,stamping said bearing carrier as a single unit from flatsheet metal stock including the steps of providing a flat sheet metalstock, embossing said flat sheet metal stock with a plurality ofrecesses on one face thereof, die-forming said sheet metal stock toimpart at least one protuberance projecting from the other surfacethereof, forming said flat sheet metal stock into a generallycylindrical tube with the embossed said one face defining the internalsurface of said tube, forming a radial flange on said tube by upsettingone end of said tube, slidably inserting the other end of said tube intothe bore of said antifriction bearing in axial abutting contact withsaid protuberance and thereafter securing said bearing on said tubeforming a clutch throw-out bearing assembly.
 2. A method of making aclutch throw-out bearing assembly as described in claim 1 wherein saidstep of forming said flat sheet metal stock into said cylindrical tubeincludes the further steps of forming coacting means on the oppositeedges of said stock, and dieforming said stock into a tubular formwherein opposed abutting edges are disposed in interlockingly engagedrelationship.
 3. A method of making a clutch throw-out bearing assemblyas described in claim 1 wherein said antifriction bearing race membersare of the thrust washer type being formed by forging.
 4. A method ofmaking a clutch throw-out bearing assembly as described in claim 1wherein said antifriction bearing race members are of the thrust washertype being formed by powdered metallurgical compacting and sinteringtechniques.